Ta có: (x+1).(3-x)=0
=> x+1=0 hoặc 3-x =0
+) x+1=0 +) 3-x=0
x= 0-1 x=3-0
x=-1 x=3
Vậy x = -1 hoặc x=3
( x + 1 )( 3 - x ) = 0
=> x + 1 = 0 hoặc 3 - x = 0
=> x = -1 hoặc x = 3
Vậy x = -1 hoặc x = 3
`(x+1).(3-x)=0`
`=>`\(\left[\begin{array}{l}x+1=0\\3-x=0\end{array}\right.\)
`=>\(\left[\begin{array}{l}x=0-1\\x=3-0\end{array}\right.\)
`=>`\(\left[\begin{array}{l}x=-1\\x=3\end{array}\right.\)